Hilary Craven has lost the will to live, Mrs Betterton is already dead. Then Hilary is asked to impersonate the dead woman and to trace her husband - a missing nuclear scientist - and her will to live returns. A faked air disaster, a string of radio-active pearls, a leper colony floundering in the dry heat of the Moroccan desert. Hilary is lead towards a terrifying discovery and her new found enthusiasm for life turns into ice-cold fear...Christie based this book partly on the activities of two famous physicists of the early 1950s: Bruno Ponecorvo, who defected to Russia, and Emil Fuchs, who spied for the Russians. It is another of Christie's light-hearted thriller novels featuring a daring and fearless heroine.